My parents and I had to change our whole day in Normandy, so we were wondering how would you spend a full day doing D-Day sites. We decided to stick directly to D-Day sites. We will have a car and starting in Caen by taking the train from Paris. Thanks! We are up to anything to do with D-Day.
Brendon, Even with a car, my preference would still be to take one of the excellent local tours. The Guides are very knowledgeable on where the significant sites are located, and they know all "shortcuts" so they take the most efficient route. The invasion front covered a distance of about 50-miles and extended some distance inland, to that's a lot of area to cover in one day, especially if not familiar with the area! I've toured sites in that area both on my own and with a tour, and found that the tour provided a much richer travel experience and a much greater view of the history. Happy travels!
I second Ken's recommendation for taking a tour or hiring a guide. If you want to do it on your own, then I would suggest picking a museum or two, visiting the American Cemetery - with a walk down to Omaha Beach - and Point du Hoc (because there's still a lot of stuff there.) If you have additional time, I would suggest looking at what's left of the artificial harbor of Arromanches and visiting St. Mere Eglise (made famous by the movie "The Longest Day"). Be sure to look for the paratroopers in the stained glass windows at the church there.